Eucocconeis flexella | Species - Diatoms of North America

Category

Monoraphid
Length Range

18-40 µm
Width Range

9-20 µm
Striae in 10 µm

22-24 in center valve

Synonyms

Achnanthes flexella (Kütz.) Brun

Contributor

Marina Potapova - Oct 2010
Reviewer

Mark Edlund - Dec 2010

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Identification

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Description

Frustules are strongly bent in girdle view with concave raphe valve and convex rapheless valve. Valves are elliptical-lanceolate with slightly drawn-out ends and deep mantles. Valve face has depressions along the margins. The raphe valve has a narrow axial area and a lanceolate-rhomboid central area. The raphe is straight or slightly sigmoid with terminal ends sharply turned to opposite directions. Rapheless valve has a narrow linear or slightly sigmoid axial area and a large rectangular or hexagonal central area. The striae are punctate, strongly radiate on raphe valve and slightly radiate on rapheless valve, 22-24 in 10 μm.

Autecology

This diatom is small in size and typically grows attached to surfaces in a prostrate manner. Cells are only slightly motile and grow as single cells (they do not form colonies). In California, this taxon is characterized within the Biological Condition Gradient (BCG) of 2, which are highly sensitive species. It has been reported from streams of the west (EPA Western EMAP, USGS Regional Survey of California) and lakes of the northeast (EPA Northeast Lake Survey).

Size Range, µm3

1001-10000
Motility

Slightly motile
Attachment

Prostrate
Habitat

Benthic
Colony

Solitary
Occurrence

Rare
BCG

BCG 2
Waterbody

Inland Rivers Lakes
Distribution

Western rivers 2004 California coastal rivers 2017 Northeast lake sediments Great Lakes inventory
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Original Description

CYMBELLA? FLEXELLA. Taf. 4. Fig. XIV, Taf. 6. Fig. VIII. (420/1). C. laevissima, mi¬nor, a latere secundario elliptica, subsigmoidea, apicibus parum productis obtusis, altero latere cur-vata, (genuflexa) dorso convexo, ventre concavo exciso, apice truncato. In Quellwasser bei Thun in der Schweiz! — Länge 1/55"'.

Basionym

Cymbella flexella
Author

Kütz. 1844
Length Range

41 µm

Original Images

Citations & Links

Citations

Cite This Page

Potapova, M. (2010). Eucocconeis flexella. In Diatoms of North America. Retrieved December 16, 2024, from https://diatoms.org/species/44846/eucocconeis_flexella

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Eucocconeis flexella from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.